nfp: don't clutter init code passing fw_ver around

Reading fw version from the BAR is trivial.  Don't pass it around
through layers of init functions, simply read it again where needed.

This commit has the side effect of each vNIC having the exact NFD
version from its own control memory, rather than all data vNICs
assuming the version of the first one.  This should not result in
user-visible changes, though.  Capabilities of data vNICs of trival
apps are identical.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>